Looper for lock-stitch sewing machines



y 5, 1950 A. LE R. AMBYE 2,516,665

LOOPER FOR LOCK-STITCH SEWING MACHINES Filed Feb. 6, 1948 Patented July25, 1950 PATE r -f o..FFics 1;}

LOOPER FOR LOCK-STITCH SEWING MACHINES Y Anthon Le'Roy Ambye, Andover,Mass., assignor I v to L. 0. Nichols, Newton, -Mass., a'firm ApplicationFebruary s, 1948, Serial No. 6,715 j My present invention is a novel andimproved construction of a looperi'for use in sewing machines, whichlooper carries the lower thread to form a lock stitch in cooperationwith the needle penetrating the work, in the well-known type of lockstitch sewing machine.

Heretofore, considerable difiiculty has been found in such looperconstructions, which were usually made of a single needle-like bar-,fusually curved and fitting in a shank and actuated to rock back andforth in a circular path to feed the lower line of thread to engage thethread loop formed by the needle as the needle penetrates the work andbefore it is retracted for the succeeding stitching action.

These loopers move or rock back and forth directly in the path of theneedle and are often struck by the needle and broken, and hence requirethe stoppage of the machine, removal of the entire looper device, andreplacement of the same.

My present improved construction obviates this difficulty to a largedegree and provides a removable looper wherein the thread-carrying partonly of the looper can be quickly removed and replaced.

Furthermore, by my present invention, this removal and renewal action ofthe thread-carrying bar of the looper is effected in a convenientposition for the operator so that the replacement of a broken bar can beinstantly efiected, saving time in the stoppage of the work, preventingthe necessity for adjustment of the shank portion of the looper in theactuating mechanism, and being instantly completed.

A further feature and advantage of my present invention consists in theeconomy and cheapness of renewing the relatively small part of thethread-carrying bar as distinguished from replacing an entire bodyportion, shank, and complete looper device. Such loopers beingnecessarily made of fine steel and of a precision construction, with agroove and eye of predetermined dimensions, which eye andthread-carrying recesses are drilled in the part apt to be so broken,involve very substantial expense. By my improved device, I replace onlythe thread-carrying bar which has formerly consisted in an integral partwith the shank, my looper needle fitting firmly into a rigid andreinforcing construction for the thread-carrying bar so that the bar canresist to a high degree the impact of the needle and, hence, prevent toa considerable extent the breakage.

Thus, by my invention of a quickly removable .1 Claim. (01.112418) .topbarin a looper, without disturbing the feeding and adjustmnt of the bodyand base-portion of the looper inthe rockingmechanismy'I also insure amore accurate replacementofparts,

as well as ease and efficiency-from the operator's standpoint, andthe"speed' ofireplacementof a broken looper.

' Referring'to the-drawings:

Fig. 1' isatopplan'view;

Fig.2 is a side elevational view;' I 1 I Fig. 3 is a side elevationalview partly in crosssection at a angle with respect to Fig. 2;

Fig. 4 is a plan view of a modification;

Fig. 5 is a side elevational view; and

Fig. 6 is a view partly in cross-section at a 90 angle relatively toFig. 5.

Referring to the drawings and to the forms shown in Figs. 1, 2, and 3,my present improved removable two-part looper construction comprises ahead I formed integral with a post 2 and a shank 3, the shank 3 beingadapted to fit within the rocking mechanism of the sewing machine andwith a flange 5 formed integrally between the post 2 and shank 3 tolimit the fitting of the shank 3 in the rocking mechanism. The head Iis, preferably, formed with a short lug or extension 8, which is tappedinwardly to receive a set screw I0, preferably of a typical socket headtype,

this set screw being threaded therein thru a correspondingly threadedportion 9 of the extension 8 and continued into the head I to intercepta transverse gored or bored opening I2, which opening is designed toreceive the shank I5 of the looper bar 20.

This bar is also formed with a flange 2| constituting a bearing fittingon the side of the head I and said bar is further bored, as shown at 22,thru which the thread carried by the looper is roved, passing along thrua groove 24 lengthwise of the bar and outwardly thru an eye 25 near apoint 26.

Thus, in assembling the removable top bar 20 in the head I, the setscrew I0 is loosened, the bar 20 removed and a new bar instantly fitted,

Ill tightened, and the looper ready These operations of loosening andthe shank 3| of the looper bar 33, which bar has a bored opening 32therethru. permitting the thread to be roved therethru and along agroove 35 to the eyelet 36 near a point 31 of the looper bar 33. Theflange 32 on the looper bar bears against the side of the head 30 andreinforces the looper bar 33 in this position. The head 39 is providedwith an-extension "38 threaded .to receive a correspondingly threadedset screw m which can be tightened against the shank 3| and quicklyreleases or looks the bar 33 in position during replacement and renewalas will be readily appreciated.

In this form, the head 30 has ofiset portions H and 45 formed with theshank which latter is adapted to be fitted in a corresponding socket inthe rock arm of the machine.

Thus it will be appreciated that my removable looper permits renewal ofthe breakable portion of the looper, viz., the top bar, by a quick,

-cnnvenient, and easily operated replacement,

when damaged or broken, and at a minimum of expense. The manufacturedthe top bar 2! or vi3 3 is a comparatively inexpensive manuiaeturingproposition as it is a short straight grooved bar wvith :ashank andifiange. The flange 2| in Figs.

1, 2, and 3, or 32 in Figs. 4, 5, and 6const-itute a stop to accuratelyfit the 'looper bar in the head and also to constitute a strengtheningand torsion-resisting element, thus tending to withstand 4. breakage ofthe top bar from impact with the sewing machine needle or other damagingblow thereto.

Thus my removable looper is positively reinforced where it fits into thesocket, by the bearing flange and the sturdy construction afforded by mydesign. Furthermore, this reinforcing feature is substantially at'th'epoint which was formerly the weakest part and where breakage was mostfrequent in old style loopers.

I claim:

Ina two-part removable looper of the kind described adapted 'for use ina lock-stitch sewing machine, comprising a head portion having a:socketrand an integral supporting post, the socket 'opening in saidhead formed to receive the shank-of removable thread-carrying looperbar, a transverse tapped opening communicating with said socket, and aset screw fitted in said tapped opening to removably secure thethread-carry- :ing :looper bar in said head.

. ANTHONLE ROY REFERENCES CITED The foliowing references are of recordin the file of this patent:

Number 3 2,312,858

